\\[-1.8ex] Soil Heterogeneity & $-$0.104$^{***}$ & $-$0.085$^{***}$ & $-$0.083$^{***}$ & $-$0.082$^{***}$ & $-$0.082$^{***}$ & $-$0.082$^{***}$ & $-$0.082$^{***}$ \\ 
  & (0.032) & (0.028) & (0.027) & (0.027) & (0.026) & (0.026) & (0.027) \\ 
\\[-1.8ex] 
Observations & 14,183 & 14,183 & 14,183 & 14,183 & 14,183 & 14,183 & 14,183 \\ 
R$^{2}$ & 0.347 & 0.376 & 0.379 & 0.382 & 0.383 & 0.383 & 0.383 \\ 
